This SLA chargers is fully automatic. When the battery is charged, the charger automatically switches to trickle charge and a green LED will show this. A red LED is lit when there is normal charging. Virtually any SLA battery can be charged, but the higher the battery size, the longer the charge.
* Short circuit and wrong polarity prevention
* Constant charging current
* No charge with wrong polarity connection
* No voltage at alligator clips until battery is connected.
Will not charge a totally flat battery ie. zero volts.